Weight-grading apparatus



Jan. 7, 1941. a LOSHAK 2,227,788

WEIGHT-GRADING APPARATU S Filed April 21, 1958 2 Sheets-Sheet 1 Jan. 7,1941. LQSHAK 2,227,788

WEIGHT-GRADING APPARATUS Filed April 21, 1938 2 Sheets-Sheet 2 PatentedJan. 7, 1941 UNITED STATES PATENT OFFICE Bernard Loshak, Boxford, nearColchester, England Application April 21,

1938, Serial No. EDS/l6!) In Great Britain April 28, 1937 8 Claims.

This invention relates to apparatus for sorting or grading articlesaccording to their weight, and particularly to articles such as fruitand vegetables of a globular shape.

It is an object of the present invention to provide an apparatus of thiskind, comprising a cradle on a horizontally pivoted beam wherein byreason of the preliminary rejection of underweight articles the gradingmechanism can operate with increased rapidity on the articles within therange of weights it is desired to grade.

It is another object of the invention to feed an article from therejecting means to the grading cradle only when the latter is inreceiving position by retaining the cradle in that position when emptyuntil it is released therefrom by the weight of an article.

It is a further object of the invention to delay the action of therejecting means. to deliver an article above the given weight into thegrading cradle when the latter is not in its receiving position.

It is a further object of the invention to provide a conveyor forfeeding the articles one at a time to the rejecting means, the conveyorbeing controlled by the latter so that it is operable only when therejecting means is ready to receive an article.

By these various means it is possible to operate a weight gradingapparatus of the kind indicated with maximum efliciency.

Other objects and advantages of the invention will be apparent from thefollowing description when read in connection with the accompanyingdrawings, in which- Fig. 1 is a diagrammatic side elevation of one formof complete grading machine;

Fig. 2 is an enlargedview of the cradles and releasing mechanism of Fig.1;

Figs. 3 and 4 are a plan and cross section of one form of feed belt, and

Fig. 5 shows an alternative form of feed mechanism.

In order to provide a compact mechanism it is desirable that the beamshall be relatively short, and in this case when there is a considerablenumber of grades of articles to be separated, it is necessary that thebeam shall be capable of swinging through a large angle in order toallow sufficient space for each grade. It is also desirable that theaxis of the cradle shall remain substantially vertical throughout itsdownward swing, so as to prevent an article from falling out of thecradle due to canting of the latter during its swing. This is effectedby providing the beam in the form of a parallel link device, as shown inFig. 1. In this arrangement the beam comprises a pair of parallel spacedarms 25 and 26 which are pivoted at their ends to two links 21 and 28.The lower end of the arm 25 is fixed on a spindle 29 rotatably mountedin bearings 30. secured to the frame 3| of the machine and the spindle29 carries a cam ll to the periphery of which is attached a cord l3which passes over a guide pulley l1, and carries the control weight I 5on its lower end. The lower end of the upper link 21 extendshorizontally towards the front of the mechanism and carries thetriangular pyramidal cradle 3 for the articles to be graded, and theother end of the link 21 is slotted or notched at 32 to engage a fixedcatch 33 on the frame which retains the cradle 3 when empty in itsuppermost position, and a fixed stop 34 is provided to limit the upwardswing of the beam and cradle. The upper end of the link 21 also carriesa projecting arm 35. The lower end of the link 28 pivots on the spindle29 and has a pin 36 on its other end which passes through a slot in aninclined fixed bracket 31, and a weight 38 is fixed to the link 28 whichretains the pin 36 at the lower end of its slot and the notch 32 on link21 in engagement with the catch 33, when the cradle 3 is empty and atthetop of its swing.

The cradle 3 is mounted on the lower end of the link 21 and has threeoutwardly inclined sides or flaps, two of which, 39 and 40, are shown.These sides or flaps are hinged at their lower edge and are retained intheir uppermost or closed position by means of catches M on the upperend of cranked arms 42 pivotally mounted in brackets 43 fixed to thebase of the cradle 3. Springs 44, Fig. 2, are provided on the crankedarms 42 to retain them in the position with the catches 4| engaging theside of the cradle flaps, which latter are urged to their closedposition, when the cradle is empty, by springs (not shown) on theirhinges.

A series of inclined and vertically spaced discharge chutes 45 aremounted adjacent the path of the swing of the cradle 3, and oppositeeach of its sides (in Fig. 1 only the chutes opposite the side 40 areshown), and each chute 45 carries a bracket 46 to the free end of whichis pivoted a finger 41, the outer end of which can swing downwards fromthe position shown but not upwards, and projects into the path of theswing of the outwardly extending end of the arm 42. The chutes not shownare spaced apart in a similar manner tothe chutes 45, but sub-divide thespaces between these chutes 45, so that each chute is disposed at adifierent level from the. others.

By employing a cradle which opens on more than one of its sides todischarge the articles as they are graded, it is thus possible toprovide a relatively large number of chutes for receiving these gradedarticles for a given are of swing of the beam, and this feature,together with the relatively short beam having a parallel linkage,results in an increase in the speed of operation of the apparatus overpreviously proposed grading machines.

The machine shown in Fig. 1 has a second cradle 48 mounted above thegrading cradle 3, the purpose of which is to eliminate articles below agiven minimum weight which have been fed to the machine and to depositthe article as lightly as possible into the grading cradle and soprevent the latter from being released by an article under the minimumweight. This cradle 48 is also of triangular shape with its rear side 48pivoted at 50 to one end of a beam 5|, and the other two sides 52 (oneonly of which is shown) are hinged together along their lower edges, thehinge 53 being secured at one end to the lower corner of the side 48,and the sides 52 are urged to their uppermost or closed position bymeans of a spring (not shown) on the hinge 53, when the cradle 48 isempty.

The beam 5| is mounted at 54 to swing vertically in a bearing fixed tothe frame 3| of the machine, and has a counterweight 55 adjustablymounted on its end opposite to the cradle 48, so that when the cradle 48is empty the beam rests in its uppermost position against a fixed stop56 on the frame.

The cradle 48 is normally prevented from swinging about the pivot 58 andheld in its uppermost position relative to the beam 5|, by means of atrigger 51 pivoted to the beam 5|, with its upper end arranged to engagea catch 58 on the back 49 of the cradle, a stop 68, Fig. 2, beingprovided to retain the trigger 51 in a position so that it can re-engagethe catch 58 after it has been released. A catch 6| is fixed on theunderside of the beam 5| adjacent the pivot 58, and is arranged toengage a spring trigger 82 mounted on an arm on the frame 3| when thebeam is at the bottom of its swing; and the trigger 52 is provided witha rearwardly projecting finger 63.

The sides 52 of the cradle 48 are retained in their closed position bymeans of catches 64 pivoted on the upper corners of the back 48, andtheir rearwardly projecting ends are arranged to engage pivoted fingers65 on the frame similar to the fingers 41 when the cradle 48 swingsvertically, so that the sides 52 are released to swing outwardly owingto the weight of an article in the cradle 48 only during the upwardswing of the latter. Also discharge chutes 66 are provided at each sideof the path of swing of the cradle 48 for receiving the underweightarticles discharged therefrom. The chute 86 and corresponding releasingfingers 65 on one side of the cradle 48 may be disposed at H a differentlevel from those on the opposite side so that underweight articleswithin two difierent limits of weight may be separated from each other.

The feeding mechanism in the apparatus illustrated in Fig. 1 consists ofan endless belt 61 mounted on rollers or pulleys 68 and driven in thedirection of the arrow by any suitable means. The outer surface of thebelt 51 is curved as shown in Fig. 4 and has depressions 69 spaced alongits length which are just sufficiently large to retain a single articleto be graded.

The articles are fed to the machine by means of an endless belt conveyor18 from which they pass down an inclined guide chute ll, on to the belt61; only one article can remain in each depression, and the others rolloil and fall on to travelling belts 12 on each side of the belt 61 andare returned to the point from which they are fed on to the conveyor'10.

As the belt 61 moves forward the articles fall from the depressions 69into the cradle 48 which then swings downward. The speed of the belt 51is regulated so that the rate at which the articles are fed to thecradle 48 does not exceed the time of a downward and return swing of thecradle.

If the article in the cradle 48 is equal to or above the given minimumweight to be graded,

the cradle with the beam 5| will swing down to the full extent of itstravel, and if the grading cradle is in its uppermost position as shownin Fig. 1, the spring trigger 62 will be pushed back by the finger 35,so that the trigger 62 does not engage the catch 8|, but the finger 63on the trigger will engage the lower end of the trigger 51 and releaseit from the catch 58, thus allowing the cradle to tip forward anddeposit the article into the grading cradle 3, after which the cradle 48and beam 5| swing back to their uppermost position, and as the beam 5|strikes the stop 56, the empty cradle 48 tips up due to its momentum, sothat the trigger 51 re-engages the catch 58 and retains the cradle 48 inposition ready to receive another article.

As the cradle 48 swings downwards the catches 64 contact with thefingers 65 and cause the latter to turn about their pivots withoutreleasing the catches 84. However, if the article deposited in thecradle 48 is below the given minimum weight, the latter will swing downthrough an angle smaller than the full extent of the swing, thus failingto discharge the article from the cradle and as it swings back the catch64 engages the finger 65 which, since it cannot move upwards, causes thecatch 64 to turn and release the cradle side 52, which then swingsoutwards due to the weight of the article, which latter is thendischarged into the chute 66; whereupon the side swings back to itsclosed position due to the spring on the hinge 53, and the cradlereturns to its uppermost position.

If the grading cradle 3 is not in position at the top of its swing whenthe cradle 48 reaches its lowest point, the latter cradle will beretained in this position by the catch 3| which engages the springtrigger 62 and the finger 63 will not contact the trigger 51 and whenthe cradle 3 returns to the top of its swing the finger 35 releases thespring trigger 62 from the catch 6| and causes the finger 83 to releasethe trigger 51 from the catch 58, so that the article is discharged fromthe cradle 48 and the latter swings back as described above.

As soon as an article is deposited into the grading cradle 3, the link21 pivots on the upper end oi the arm 25, thus releasing the catch 33and causing the pin 38 to move to the upper end of its slot in thebracket 31, the weight 38 being adjusted so that the lightest article tobe graded will release the catch 33 when placed in the grading cradle 3.

The cradle 3 then swings downwards and the extent of this swing is thegreater according as the weight of the article in the cradle is greater,

and during this downward swing the cord I3 wraps round the curvedperiphery of the cam so that the leverage of the balance weight I5 isincreased as the extent of the swing increases, and the contour of thecam is of such a shape that the beam and grading cradle 3 swing throughsubstantially equal angles for each equal increment of weight added tothe grading cradle.

As the grading cradle descends the projecting ends of the cranked arms42 depress each of the fingers 41 in turn as they swing past, withoutreleasing the catches 4|. When the cradle commences its return swing oneof the projecting arms 42 contacts the underside of the lowest finger 41which it has just passed, and since this latter finger cannot move up,the projecting arm 42 is pressed down thus releasing the catch 4|, sothat the corresponding side of the cradle swings out on its hinge underthe weight of the article, which latter is discharged into thecorresponding chute 45, and the cradle side swings back into its closedposition, the outer face of the catch 4| being bevelled to allow thecradle flap to move past, after which the cradle 3 swings back to itsuppermost position and is retained by the catch 33 ready to receiveanother article.

The feeding mechanism shown in Fig. 5 consists of an endless belt 13mounted on pulleys or rollers 14 which are free to rotate in the fixedframe 3| of the machine. Attached to the outer surface of the belt 13throughout its length is a series of spaced shallow cups 15 which arejust sufliciently large to hold a single article to be graded; alsoprojecting from one side of the belt is a series of pins 16 spaced apartat a distance equal to the spacing of the cups 15. An approximatelyZ-shaped member is pivoted at about its centre to an arm of the frame 3|and is urged by a spring 18 so that its: downwardly directed armcontacts the beam 5|, when the latter rests against the stop 56, and sothat its upwardly directed arm 1! extends into the path of travel of thepins 16.

The articles are fed into the cups 15 on the upper sloping run of thebelt 13, and travel down by their own weight towards the cradle 48 intowhich they are discharged. When this cradle 48 is in its uppermostposition, as shown, the beam 5| presses up the left hand arm of themember 11 so that its right hand arm is moved out of the path of thepins 16 to allow the belt 13 to rotate. When an article is deposited inthe cradle 48 and the beam 5| moves down, the member 11 turns about itspivot so that its right hand end comes into the path of the pins 16,thus preventing further feeding movement of the belt until it is againreleased when the beam 5| returns to the top of its swing.

If desired the upper cradle 48 may be omitted from the machine so thatthe articles will be fed directly into the grading cradle 3, in whichcase, if the feeding mechanism shown in Fig. 5 is employed, means may beprovided on the parallel link beam for operating the feed release member11.

Also, if desired, the cradle may be of other than triangularcross-section and one or more of its sides may be formed as hinged flapsas described, the remainder being fixed, in which case it is onlynecessary to provide discharge chutes opposite the sides which arearranged to open.

What I claim is:

1. Apparatus for grading articles according to weight, comprising incombination a beam pivoted at one end on a fixed horizontal axis,

a grading cradle on the other end of the beam, a balance weight soconnected to the pivoted end of the beam that the leverage of saidweight is progressively increased as the extent of the downward swing ofthe beam is increased, means whereby an article is released from thegrading cradle adjacent the bottom of its swing, means such as a secondpivoted beam and cradle disposed above the grading cradle and adapted atthe bottom of its swing to deposit an article above a given Weight intothe grading cradle and to reject an article below the given weight onits return swing, a catch associated with the first named beam wherebythe grading cradle is retained in its top position when empty, and isreleased therefrom by the weight of an article in said grading cradle,and a further catch associated with the second cradle whereby saidsecond cradle, when loaded with an article above the given weight, isretained at the bottom of its swing when the grading cradle is not inits top position.

2. Apparatus for grading articles according to weight, comprising incombination a beam pivoted at one end on a fixed horizontal axis, agrading cradle on the other end of the beam, a balance weight soconnected to the pivoted end of the beam that the leverage of saidweight is progressively increased as the extent of the downward swing ofthe beam is increased, means whereby an article is released from thegrading cradle adjacent the bottom of its swing, means such as a secondpivoted beam and cradle disposed above the grading cradle and adapted todeposit an article above a given weight into the grading cradle at thebottom of its swing and to reject an article below the given weight onits return swing, an endless conveyor disposed above the second cradle,whereby articles to be graded are fed singly to the second cradle, andfeed control means operated by the second named beam, whereby the feedconveyor is operable only when the second cradle is in its top position.

3. Apparatus for grading articles according to weight comprising incombination a beam pivoted on a fixed horizontal axis, a grading cradleon the beam, means for varying the downward swing of the beam accordingto the weight of an article loaded into the cradle, rejecting meansadapted to deposit an article above a given weight into the gradingcradle and to reject an article below the given weight, means whereby anarticle is released from the grading cradle adjacent the bottom of itsswing, and means whereby the said grading cradle is retained in itsreceiving position when empty and is released therefrom by the Weight ofan article in the said grading cradle.

4. Apparatus for grading articles according to weight comprising incombination a beam pivoted on a fixed horizontal axis, a grading cradleon the beam, means for varying the downward swing of the beam accordingto the weight of an article loaded into the cradle, rejecting meansadapted to deposit an article above a given weight into the gradingcradle and to reject an article below the given weight, means whereby anarticle is released from the grading cradle adjacent the bottom of itsswing, means whereby the said grading cradle is retained in itsreceiving position when empty and is released therefrom by the weight ofan article in the said grading cradle, and means whereby the action ofthe rejecting means to deliver an article above the given weight intothe said grading cradle is delayed when the said grading cradle is notin its receiving position.

5. Apparatus for grading articles according to weight comprising incombination a beam pivoted on a fixed horizontal axis, a grading cradleon the beam, means for varying the downward swing of the beam accordingto the weight of an article loaded into the cradle, rejecting meansadapted to deposit an article aboe a given weight into the gradingcradle and to reject an article below the given weight, means whereby anarticle is released from the grading cradle adjacent the bottom of itsswing, a conveyor whereby articles to be graded are fed singly to therejecting means, and feed control means operated by the rejecting meanswhereby the conveyor is operable only when the rejecting means is readyto receive an article.

6. Apparatus for grading articles according to weight, comprising incombination a beam pivoted at one end on a fixed horizontal axis, agrading cradle on the other end of the beam, a balance weight soconnected to the pivoted end of the beam that the leverage of saidweight is progressively increased as the extent of the downward swing ofthe beam is increased, means whereby an article is released from thegrading cradle adjacent the bottom of its swing, rejecting meansincluding a second pivoted beam and cradle disposed above the gradingcradle and adapted at the bottom of its swing to deposit an articleabove a given weight into the grading cradle and to reject an articlebelow the given weight on its return swing, a catch associated with thefirst named beam whereby the grading cradle is retained in its topposition when empty and is released therefrom by the weight of anarticle in said grading cradle and a further catch associated with thesecond cradle whereby said second cradle, when loaded with an articleabove the given weight, is retained at the bottom of its swing when thegrading cradle is not in its top position.

7. Apparatus for grading articles according to weight, comprising incombination a beam pivoted at one end on a fixed horizontal axis, agrading cradle on the other end of the beam, a balance weight soconnected to the pivoted end of the beam that the leverage of saidweight is progressively increased as the extent of the downward swing ofthe beam is increased, means whereby an article is released from thegrading cradle adjacent the bottom of its swing, rejecting meansincluding a second pivoted beam and cradle disposed above the gradingcradle and adapted at the bottom of its swing to deposit an articleabove a given weight into the grading cradle and to reject an articlebelow the given weight on its return swing, an endless conveyor disposedabove the second cradle whereby articles to be graded are fed singly tothe second cradle, and feed control means operated by the second namedbeam whereby the feed conveyor is operable only when the second cradleis in its top position.

8. Apparatus for grading articles according to weight, comprising incombination a beam pivoted on a fixed horizontal axis, a grading cradleon the beam, means for varying the downward swing of the beam accordingto the weight of an article loaded into the cradle, rejecting meansadapted to deposit an article above a given weight into the gradingcradle and to reject an article below the given weight, means whereby anarticle is released from the grading cradle adjacent the bottom of itsswing, a retaining latch operative to hold the cradle in its receivingposition as long as the cradle is empty, and means actuated by thearticle being deposited into said cradle for releasing said latch topermit said beam to be depressed in accordance with the weight of thearticle to be graded.

BERNARD LOSHAK.

